1. Field of the Invention
The present invention relates to a resist pattern thickening material which thickens a resist pattern by being applied onto a resist pattern that is formed of an ArF resist, may form a fine pattern exceeding exposure limit of optical source of an exposure device, and allows for improving etching resistance of the resist pattern; a resist pattern which may be patterned by an ArF excimer laser and the like, has a fine structure, and is excellent in etching resistance; and an efficient process for forming the resist pattern; a semiconductor device having a fine pattern formed by the resist pattern, and an efficient process for manufacturing the semiconductor device.
2. Description of the Related Art
Recently, a semiconductor integrated circuit is highly integrated. LSI and VLSI have been utilized. Accordingly, a wiring pattern now reaches the range of less than 0.2 μm, and the minimum pattern is 0.1 μm or less. In order to form a fine wiring pattern, it is very important to take advantage of lithography, which refers to the steps to cover a treating substrate formed of thin films by a resist film, to form a resist pattern by developing after selectively exposing light, and to carry out dry-etching by using the resist pattern as a mask. Thereafter, it is also very important to obtain a desired pattern by removing the resist pattern.
In order to form a fine wiring pattern, it is necessary both to shorten a wavelength of optical source of an exposure device, and to develop a resist material which has a high resolution based upon properties of an optical source. However, in order to shorten the wavelength of the optical source at the exposure device, it is indispensable to renew an exposure device, which results in considerable expenses. Developing a resist material which suits an exposure with a shorter wavelength is not very easy.
A process of manufacturing a semiconductor device includes first forming a fine pattern by resist pattern, and then finely using the resist pattern as a mask. Therefore, the resist pattern is preferably excellent in etching resistance. However, the newest technique, an ArF (argon fluoride) excimer laser exposure, has a problem that a resist pattern used for the exposure is insufficient in etching resistance. It is possible to use a KrF (krypton fluoride) resist, but the KrF resist sometimes has insufficient etching resistance in a case of a severe etching condition, a thick treating layer, forming a fine pattern, and having a thin resist thickness. There has been a request for a technique to form a resist pattern excellent in etching resistance, and to form a fine pattern by using the resist pattern.
A technique called RELACS is described in Japanese Patent Application Laid-Open No. 10-73927, in which a fine pattern can be formed by use of KrF (krypton fluoride) excimer laser (wavelength: 248 nm) of deep ultraviolet beam as the exposure light for a resist. This technique comprises forming a resist pattern by exposing the resist (positive type or negative type) with the KrF (krypton fluoride) excimer laser (wavelength: 248 nm) as the exposure light, providing a film by use of a water-soluble resin composition so as to cover the resist pattern, making the film interact with the resist pattern in the interface by use of the residual acid in the material of the resist pattern to thicken (hereinafter often referred also to as “swell”) the resist pattern, thereby shortening the pitch between resist patterns to form the fine pattern.
In that case, however, the KrF (krypton fluoride) resist is an aromatic resin composition such as novolac resin, naphtoquinodiadido, and the like. Since an aromatic ring contained in the aromatic resin composition absorbs the ArF excimer laser light, the ArF (argon fluoride) excimer laser light is unable to transmit the KrF resist. Therefore, the ArF (argon fluoride) excimer laser light, which has a shorter wavelength than the KrF excimer laser light, cannot be used as the exposure light.
From the viewpoint of forming a fine wiring pattern, it is preferable that the ArF (argon fluoride) excimer laser light can also be used.
Accordingly, a technique to form a fine pattern excellent in etching resistance with low cost, by using the ArF (argon fluoride) excimer laser light as an optical source of an exposure device when patterning is not yet provided.